Field of the Invention
The present invention relates to trailer hitches and more particularly to a removable, interchangeable trailer hitch ball mountable on a trailer hitch for detachably connecting a trailer with a towing vehicle. Conventional trailer hitch balls are forged or upset from a uniform stock of metal and then machined to a final finished spherical configuration necessitating the use of a certain amount of material of uniform hardness and resulting in waste material.
U.S. Pat. Nos. 5,419,576; 5,290,057; 5,116,072; 4,938,496; 4,889,346; 4,772,039; 4,522,421; 4,596,406 and 4,433,854 all disclose removable and interchangeable trailer hitch balls that facilitate removal and replacement of one size ball on a stud or post with a different size ball to properly fit various sizes of sockets on a trailer coupler typically provided on a trailer tongue. While these balls have a central bore to receive the stud or post they are substantially solid with only slight clearance between the side of the stud and the bore of the ball to permit the ball to be slid onto the post. Thus, these balls are relatively heavy and expensive to manufacture.
Certain of the prior art interchangeable hitch balls employ a locking pin extending horizontally through the side of the ball and a cross bore in the stud to secure the substantially solid ball onto the stud. However, none disclose a hollow hitch ball or retractable detent ball on the side of the locking pin that protrudes between the side of the stud and the inside of the hollow hitch ball.
Many of the prior art interchangeable balls permit rotation of the ball relative to the post. However, this can cause internal wear between the post and the bore of the ball. None of the prior art discloses permanently orienting the locking pin transverse to the direction of vehicle travel to prevent the pin from jarring loose in use and possibly falling out.
U.S. Pat. No. 2,768,848 discloses a hollow trailer hitch ball that is permanently secured to a mounting stem. This hollow ball is formed by a punch and die which presses a flat sheet metal blank into a spherical shape. However, this ball cannot be removed or interchanged with other balls of different sizes.